Hey folks, I just got my motor back from the machine shop below are the specs.

350 .040 bore
vortec 906/062 heads with 1.5 roller tip rockers, guide plates, screw in studs, and some port work.
.488/510 lift cam with 107/117 lobe separation cam link is here http://jamsionline.com/chevy-sbc-350-5-7l-hp-stage-4-488-509-lift-cam-camshaft-mc1995/
flat top pistons were installed
new pushrod, bearings, bolts, everything is new.
new plugs and wires
edelbrock 600cfm carb
Transmission is a th400 with a manual valve body and a 3000rpm stall.
b&m ratchet shifter
Running 95 octane fuel
stock crank

Broke in cam per machinists recommendation 1800rpms for 20 minutes, took the motor out and did the break in procedure kept my foot off the floor.

Here is where I am now, got a couple hundred miles on it, i tried to get into it a little today and going by the tachometer in 1st, 2nd or 3rd it wouldn't clear the 4000rpm mark. I expect this motor would turn over 6k machinist told me to keep it under 6-6500. It seems to have plenty of power, you can hear the 4 barrels open when you open it up, but it just feels like it should have way more.

Any thoughts, ideas, things to check?

So far I have adjusted the throttle linkage (this allowed the carb to open).
getting 13.6volts running (hei distributor doesn't like under 12v).
rechecked timing (34* total I believe initial was 14 or 16) vacuum advance unhooked when timing.

 

Valve springs?

Crappy cam, but it's too late now. Best you can do is optimize it.

 

Machinist said 105,(or maybe 110) with a 60 shim they were new/ordered and installed at his shop

 

And they are … ? They have a part #, no doubt?

 

02-1000-16 is what's wrote on my receipt. I can only assume it is these https://sandiegoengineparts.com/prod...ngs-02-1000-16

 

Cams in that lift range are usually asking for about 120-130lb springs.

I don't even understand the concept behind that camshaft. They Going for the worst idle quality possible with that? This is one of those car show cams isn't it?

GD

 

No car show at all, motor originally had a .480 lift, told the machinist I liked the sound of the rough idle and that's what he recommended

 

That's the old "Edelbrock RPM" cam. Had lots of names before that. People have been HATING it for 40 years that I know of; probably longer. It wasn't new when I first met it.

Butt hay, it's in there, just gotta do what needs to be done to not make it quite so much of an obsolete EFFF-up. Valve springs are the place to start. Let's hope that no push rods are bent yet, or anything more expensive and difficult to fix.

Those are NOWHERE NEAR enough spring. Hardly even enough for a 929 cam. Whether that's "The Problem", I can't know; but they're SURE AS HELL not part of the solution.

 

In the future, I'd look to someone else for cam and spring advice.

2-1000-16 Specifications
Spring O.D.: 1.230
Spring I.D.: 0.876
Closed Height: 1.700
Closed Load: 91
Open Height: 1.250
Open Load: 233
Coil Bind: 1.150
Max. Lift: .525
Rate: 316

CALL AND MAKE SURE THOSE ARE THE SPRINGS HE USED. Sounds about right though because if he used a .060” shim on those springs it would put the seat pressure right at 110#. However, the problem is the shim puts the spring’s installed compressed height at 1.64” (1.700 -.0.060). With a binding height of 1.150”,,,, that means it will go into coil binding at .490” lift.

If those are the springs, I hate it for you, but DO NOT run it any more. Doing so could wipe the lobes on the cam, bend the push rods, and/or collapse the lifters - if it hasn't done one or more already.

 

EXACTLY
You MUST STOP RIGHT NOW and measure ALL the valvetran clearances - IF it's not too late already!

 

https://www.alexsparts.com/valve-spr...ssure-vsk4h52/

https://www.alexsparts.com/valve-spr...ssure-vsk4h53/

This kit will get you straightened out - IF no damage has already been done.

 

That's some disappointing news, but I get it. I'll swing by his shop this morning and get verification on the springs/shims. I know the push rods weren't stock, he mentioned it could bend them if they were.

So where's the starting point, measuring valve train clearances? Pulling the valve covers and checking to make sure there arent any bent push rods?

 

Pop a few valve springs off. Check the condition of the valve guide seals, if any. Look closely at the rocker arms and see if there's any sign of stress on those. Roll the push rods on a piece of window glass to check if they're bent.

The springs you have are not strong enough and are made of too thick wire. They are going into "coil bind", which is where they are fully compressed with the coils smashed against each other. Since metal is not compressible, this puts EXTREME stress on the cam lobes, lifters, push rods, retainers, and keepers. Since they don't have enough pressure to control the valve motion, the valves "float"... which occurs at the moment they are supposed to close, and actually is the valves bouncing off their seats in the head. That's what's limiting the RPMs the engine is capable of running at. They may even have been contacting the pistons, particularly the exhausts, since at the instant they close, the piston is at or very near TDC, on the opposite instance of TDC from firing.

There are few ways to ruin more stuff faster, than inadequate valve springs. It's fortunate that you noticed that something was wrong before a spring or retainer broke and dropped the valve into the cylinder.

I wouldn't bother with "shop". He'll go right straight into a$$-covering mode, probably try to tell you he's done this however many times and never had any trouble. Best to just handle it on your own.

I'm not a big fan of Alex's myself. If I were in your situation I would get:

Springs https://www.texas-speed.com/p-1383-l...od-to-550.aspx
Retainers https://www.summitracing.com/parts/cca-787-16
Keepers https://www.summitracing.com/parts/cca-648-16
Seals https://www.summitracing.com/parts/fel-ss72861
Shims https://www.summitracing.com/parts/cca-4757
Tools https://www.summitracing.com/parts/sum-900032 and https://www.summitracing.com/parts/sum-906784
Valve cover gaskets https://www.summitracing.com/parts/fel-vs50088r

Let's hope the valves, rockers, and push rods are OK... if they're damaged, they'll have to be replaced too.

And as said, DO NOT run the engine ANY MORE until this is done.

 

If anyone is having trouble understanding/ visualizing the effects of bad cam and valve spring matching, Power Driven Diesel just had a video over valve springs including install height, seat pressure, nose pressure, and coil bind. Even though the items are aimed at diesel engines, the concept is the same. It's worth the watch due to the physical demonstrations with a coil spring gauge.

 

Sounds like that's the route I'll be going. I was in the shop when he installed the springs, bolted on the heads and adjusted the valves.

I recall him mentioning coil bind, from what I could tell he would roll the motor over til one lifter on the cylinder was all of the way up, then adjusted the one that was all of the way down to 0 lash then 3/4 turn. After they were all done he had a gap gauge and checked them all (not sure what the gap was)

This is the first motor I've had at a machine shop/had built. I've done some tear down and back yard mechanic type stuff but this is a little above my head.

 

The adjustment you speak of is lifter preload. Not sure what gap he might have measured. If he tried to measure the space between spring coils at that time, the lack of oil pressure to the lifters would have concealed how far the valves would actually have been open while running, and made it appear that there was clearance when in fact there was none, or even interference.

 

Makes sense to me, I had that thought in my head at the time, lifters weren't pumped up so I didnt figure the adjustments would be right.

I'll likely pull the heads, get the parts you linked me and take them to a different shop and have them assembled. The rocker arms that came on these heads (came with the motor) are 1.5 roller tip rockers but have a 5/8" nut which makes it difficult to get a socket on them and adjust anything once you get a bit of pressure on them. Probably wouldn't hurt to replace those too, not sure if I can just get a smaller set of nuts or not

 

You can do the assembly yourself, if you buy those tools. I'd strongly suggest doing that rather than a shop. Also, if you do pull the heads, the spring compressor I linked isn't the best; it's intended for the heads to still be installed; the style that looks like a giant C-clamp might work better for heads off the motor.

Rocker nuts are pretty much always 5/8". Just use a thinner socket.

His adjustment was probably reasonably correct; just not the measurement afterwards.

 

I'll leave them on if it's not necessary to pull them. Just didn't want to drop anything down them accidentally. I've dumped some money into this thing and I really don't want it to be trashed before I ever get to use it.

 

If you choose to do this with the heads still installed, you MUST make sure that the piston for the set of valves you are working is up at the top. Otherwise the valve drops down into the cylinder, and then you ARE removing the cylinder heads.

This is actually a job that you should do yourself. And you will gain valuable knowledge in the process. Plus, we are here to guide you.

 

Spoke with the guy at the shop. He did verify those springs, and the 60 shim on them. Said 110lbs was what he measured seat pressure I believe was his wording. He did the valves, 0 lash and 3/4turn.

Lifters were not soaked in oil, installed with lube on bottoms of the lifters.

He was curious as to my issues and I explained them to him, a gentleman he built the same motor for was called and said it's still running fine/will turn 6-6.5k and slide the truck all over. That gentleman said he set valves at 0 lash and 1/4 turn (same heads,springs,cam, etc.)

I'm still on board with replacing the springs, etc. I definitely don't want a wasted investment that wont last. He did say if I wasnt happy and i felt something wasn't right he would replace the springs for me at no labor cost just the cost of the difference in parts.

 

If he measured 110# on the seat, then those springs are a little weak, because ALL springs will relax about 10# after they are run.

 

My head hurts from this. The MACHINIST, whose JOB is mostly basic math and some tooling skills plus (hopefully) some experience, doesn't seem to grasp that he installed springs that will bind at 490 on a cam with 510 lift. This won't end well. On the bench it would look ok because the lifters are empty.

GD

 

If he used those springs and 0.060" shims to get 110#, then based on their specs, that means the springs are at 1.64" as speculated. So, you are definitely going into coil bind on the exhaust side. If you were there when he installed the valves in the heads, I'm guessing you didn't see him use a valve spring height micrometer in the valve spring pockets. Should be easy to see and check the coil bind just by popping off the valve covers.

He sounds like he wants to be reasonable about replacing the springs, but I don't think I would want him to do it. I'm also going to guess he would want you to pull the heads and bring them to him.

Look at those rocker arms really good. Those stamped rockers with the roller tips are notorious for failures when everything is right. Also, many don't have a long enough slot for higher lift cams. So, make sure there's no contact in the slot area - if there is it should show up on the rocker stud also.

I'd seriously recommend you pull the intake and take a look at the lifters to make sure they don't show any wear.

 

Will be pulling the intake today, the front of the intake has a vacuum leak, not enough silicone in one corner I assume. I'll visually inspect everything once it's off. The 110# was prior to the shim, but I do agree on the more spring. I cannot see any wear/coil binding just by looking at everything with the valve cover of.... but I know you folks are trying to steer me in the right direction and wouldn't be telling me this if it weren't true. I fully trust yalls advice.

i could pull the heads or trailer it to him to replace the springs, but I've no issue buying the right stuff and making this a learning experience, so I know what I will have, and I will be able to work on it again if needed.

 

You should be able to see the springs stacked up. If not, then the valves might be longer than stock and they're installed higher than 1.64". If that's the case it might not be going into coil bind. However, that would mean the seat/closed pressure is even less than advertised - or maybe the .060" shim brought it to 1.7", which would mean no coil bind but only 90# seat. I was going by adding the .060" shim to bring the pressure to 110# based on the specs listed for the springs.

Can you take a picture of the heads with the valve covers off focusing on the springs?

It might be that there is no binding and the preload adjustment on the lifters are off.

No offense meant, but make sure the spark plugs are correct for the vortec heads - back when people first started doing all these vortec head swaps they were still buying for the car and not the heads.

EDIT - If there is a vacuum leak at the head/intake area, it has nothing to do with a lack of silicone at the china wall - it could be there was too much used and it lapped over onto the intake gasket and dried before the intake was bolted down. Hopefully it's something like that. Look at the intake gasket and see how the intake is "biting" into it. There should be an even imprint from the intake. If you see it biting in more at either the top of the bottom and not touching on the opposite end, depending on how bad it is you may be able to use a thinner or thicker gasket to raise or lower the intake for a more even sealing surface. Post pictures if you can.

 

You'll probably have to pull rockers and push rods to check for damage.

You most likely won't be able to see coil bind with the engine not running. The lifters won't be up to their full length without oil pressure, which means the valves won't be getting fully opened. That's the same mistake the shop made when he thought he was checking for bind.

The rockers will probably show damage in the push rod seat, if anywhere. If they're decent rockers, not the crappy stamped sheet rubber like stock with just an eye-candy roller in the tip, then they won't flex. The ball seat probably didn't suffer but might have. The 2 most likely parts to fail in that situation are the push rods (bending) and the studs pulling out of the heads. Bent push rods will make a clicking sound when rolled on a sheet of glass. You can check for pulled studs by laying a straightedge, a level or something, over the top of all the studs. Most often they don't all pull the exact same amount, so if they're all the same height, they're probably OK. If one or maybe a couple are noticeably higher than the others then those are pulled and you'll need to take care of that. At that point you probably would need to pull the heads and take them to a machine shop, a GOOD stud replacement isn't something for a DIYer.

If your push rods are bent, replace with these https://www.texas-speed.com/p-8292-t...set-of-16.aspx. I'm pretty sure yours are 7.400" but don't take my word for it, measure to make sure. You could even buy the Comp adjustable push rod https://www.summitracing.com/parts/cca-7702-1 and be certain.

 

Prior to pulling the intake I found a leak at the front drivers corner. Carb cleaner pointed it out very quickly. I pulled the intake and resealed it. Laid a straight edge across the screw in studs and they're all even, I rolled the engine over and watched the springs none of them looked like they were in any sort of bind. I did readjust the valves (shop did 3/4 turn after 0 lash) I started it up got oil everywhere and backed them off (several way off) til they started to click then went in 1/4 turn at a time until they stopped. I have one with a small amount of chatter still I'm going to address I think I left it a little loose.

Spark plugs are specific for vortec heads (when I acquired the motor) they had ac delco 44 spark plugs the old style. I replaced with ac delco r44lts6 plugs.

The fuel filter has bubbles in it currently so I believe I have a pinhole in a line somewhere. I assume the filter should never have bubbles in it while running.

I sprayed all around the intake, carb and dizzy looking for additional leaks and found none.

pulled the pushrods when I had the intake off and all were straight (rolled on glass, no click no uneven pieces)

Possible fuel issue? Intake sucking air? Valves over tight? All of these seem to be issues I've discovered.

When the engine was tore down it had two busted pistons (detonation) the vehicle it came out of the throttle linkage was wrong and the 4 barrels never opened, timing was never set, and the wrong plugs were used. The cam that came out was a .488 lift CS-186r by speed pro/sealed power. The springs used were stock 80lb vortec springs, that's why I went bigger (shops recommendation).

Not sure if any of this is helpful information or not. Perhaps I'm in the right direction? Or pissing in the wind?

 

That Speed Pro cam, if memory serves, is the old "Stage 2" cam you always hear about... a real generic thing from the late 60s early 70s... 230°/.480" both lobes, but old-style ramps, from back before there were very many good valve springs available. An even older design than the one you have now. But stock Vortec springs are totally inadequate for it. For comparison purposes, a Comp 280 Magnum (newer design, only 35 yrs old or so), also 230°/.480" single pattern, is 280° on the seat where that older one is 286° or thereabouts, which should give you an idea of the difference in "intensity" that cam designs can have. The ramps are far less steep than the Magnum, or even your current one, let alone anything truly modern, with what the proliferation of MUCH better valve springs there has been in recent years has allowed cam designers to do.

The air & fuel problems are pretty typical for a hot-rodder motor; just, all in a day's hobby, the kind of thing you learn to overcome. We've all been there.

Most likely place for the fuel system to have a leak that sucks air is the little short piece of hose that connects the gas tank to the car. Usually when that hose goes bad it leaks a certain amount of gas too, you can usually see it. Pretty sure if you get up under there and look, it'll be obvious, if that's the problem.